Howdy,

If you are using tap water that is where the problem is.  There are many elements which are dissolved in tap water which ionize the water.  This causes the water to be a low value resistor.  Thus inducing a lot of current through the water, and generating a lot of heat.  Any sort of electrolyte will cause the water to be ionized and will result in a lot of current being drawn from the battery.

You need to use pure water.  Deionized filtered water and distilled water are both pure water.  Reverse osmosis water can still contain ionizing agents.  Also using DC current is the very most crude way of trying to extract HHO.  You need to use a Pulsed Direct Current or Alternating Current.  I am experimenting with using a biamped audio amplifier to extract HHO from distilled water.  The intended effect is to expose the water to a two phase alternating current at a specific frequency.  Finding the right frequency is key to cracking the molecular bond of the H2O molecule and generating a bonded gas called HHO.

Water is a very complex thing.  In your science class it was presented to you as H2O.  However, if you look at water in its various forms it easily ionizes and complicates the HHO equation drastically.  One would think that fresh rain water is pure water, it is not.  Falling through the atmosphere is it ionized by pollutants in the air.  What ever surface it hits first might have elements on it which can ionize the water.  The collection container might be contaminated also.  To eliminate all these factors from the equation go buy pure distilled water to put in your experimental HHO chamber.  You'll save yourself a LOT of headaches.  One headache being the contaminants building up on your electrodes.

The current alone isn't doing the work.  Running a large amount of current through ionized water causes the water to heat up.  If you are seeing vapor it is probably water vapor and not HHO.  This is why you want to use pulsed DC or AC.  The change in voltage across the water at specific frequencies and harmonics will cause the effect you are looking for.  The water molecule has a specific vibratory rate.  If you induce a frequency that disrupts that vibratory rate you will break the molecular bond and the water will rearrange itself into HHO.  Many people have done this, but the public knowledge is scarce.  I am trying to do this myself.  I'll let you know when I figure out the specific frequency, or frequencies.  Another idea that I have been toying with is to use a dissonant chord to break the molecular bond.

OK, happy experimenting...

Blessed Be Brothers...